The long-term ojective of these studies is to understand how the synthesis of specific temporally expressed proteins is regulated in the mammalian testis. Emphasis will be placed upon establishing the function of a unique testicular a-tubulin and defining the cis-acting regulatory sequences in the genomic DNA of this tubulin and several other haploid gene products including the two protamines. Additional studies will explain how coordinate expression of genes in pre-meiotic, meiotic and post-meiotic testicular cells is controlled. Specific projects to be undertaken include: 1) determining the localization in testicular cells by immunofluorescence of the unique post-meiotically synthesized mouse a-tubulin. 2) determining whether a common DNA enhancer sequence regulates the synthesis of the protamine, a-tubulin, and other coordinately expressed haploid genes. 3) identifying specific cDNA and genomic clones for pre-meiotic and meiotic testicular cell-types to allow a direct comparison of genomic regulatory signals to be made between different classes of temporally regulated genes. 4) establishing the relationship between DNA methylation and the gene transcription and nuclear geome condensation with our growing collection of cell-type specific probes. These studies on the molecular basis for gene regulation in the testis will enhance our knowledge of basic control mechanisms during spermatagenesis, provide necessary probes to understand molecular causes of infertility, and provide superior approaches to fertility control.